The conventional bicycle speed changing device is operated by the swivelling lever such that the guide wire is actuated so as to attain the speed-changing action. This type of the bicycle speed changing device is rather inefficient at best in view of the fact that the device is often difficult for a bicyclist to maneuver after the device is located at a certain operating position or angle.
There is another conventional type of the bicycle speed changing device which is operated by two rods and is relatively complicated in construction, thereby resulting in a unreliable operation as well as a substantial increase in the production cost.